Polymerizing small molecular acceptors for efficient all-polymer solar cells

Abstract

All-polymer solar cells (all-PSCs) have received attention due to their morphological stability under thermal and mechanical stresses. Currently, the highest reported power conversion efficiency of all-PSCs is over 17%, achieved by utilizing polymerized small molecular acceptors (PSMAs). However, the need for higher regiospecificity to avoid forming isomers during polymerization of SMAs still challenges the further applications of all-PSCs. From this perspective, we focus on some recent studies and highlight the importance of controlling the regioregularity of PSMAs. In particular, integrating PSMAs with regioregularity endows the polymer acceptors with good absorption, superior backbone ordering, and optimal blend morphology compared with those obtained from regiorandom one. Moreover, the distinctive features that are derived from these regioregular PSMAs, such as the possibility of repeatable synthesis and reproducible device performance, herald a brighter future for scaling-up and commercializing all-PSCs. We expect this integrated strategy will inspire researchers to devote more efforts to further narrow the efficiency gap between the PSCs based on SMAs and PSMAs. Finally, we discuss the existing challenges and future prospects of PSMAs as new platform for further advancing all-PSCs.